e in the struggle
for existence the latter ought to have exterminated the former. Or, to
quote the most recent expression of this view, "in every locality there
would only be one species, and that the most highly organized; and thus
a few superior races would partition the earth amongst them to the
entire exclusion of the innumerable varieties, species, genera, and
orders which now inhabit it[45]." Of course to this statement it would
be sufficient to enquire, On what would these few supremely organized
species subsist? Unless manna fell from heaven for their especial
benefit, it would appear that such forms could under no circumstances be
the most improved forms; in exterminating others on such a scale as
this, they would themselves be quickly, and very literally, improved off
the face of the earth. But even when the statement is not made in so
extravagant a form as this, it must necessarily be futile as an
objection unless it has first been shown that we know exactly all the
conditions of the complex struggle for existence between the higher and
lower forms in question. And this it is impossible that we ever can
know. The mere fact that one form has been changed in virtue of this
struggle must in many cases of itself determine a change in the
conditions of the struggle. Again, the other and closely allied forms
(and these furnish the best grounds for the objection) may also have
undergone defensive changes, although these may be less conspicuous to
our observation, or perhaps less suggestive of "improvement" to our
imperfect means of judging. Lastly, not to continue citing an endless
number of such considerations, there is the broad fact that it is only
to those cases where, for some reason or another, the lower forms have
not been exposed to a struggle of fatal intensity, that the objection
applies. But we know that in millions of other cases the lower (i. e.
less fitted) forms _have_ succumbed, and therefore I do not see that the
objection has any ground to stand upon. That there is a general tendency
for lower forms to yield their places to higher is shown by the gradual
advance of organization throughout geological time; for if _all_ the
inferior forms had survived, the earth could not have contained them,
unless she had been continually growing into something like the size of
Jupiter. And if it be asked why any of the inferior forms have survived,
the answer has already been given, as above.

[45] Syme, on th